Well control head



Oct. 23, 1945. E. J. RoAcH ETAL 2 WELL CONTROL HEAD Filed Dec. 16, 1941 2 Sheets-Sheet l ll E 1.

2 E 1 i r .31. J. .Ziaaalz I Oct. 23, 1945. E. RoAcH ETAL 2,387,610

WELL CONTROL HEAD Filed Dec. 16, 1941 2 Sheets-Sheet 2 J .2 (Tanks, 7?:

Patented Oct. 23., 1945 WELL CONTROL HEAD Edmund J. Roach and Edward F. Cooke, Jr., Beaumont, Tex.

Application December 16, 1941, Serial No. 423,212

4 Claims. (CL 166-14) This invention relates to casing control heads in which the slip bowl unit which suspends the inner casing from the casing head is characterized by having captive slips, that is to say, having slips which are irremovable from the slip bowl whenever the inner casing is in place within the slip bowl.

One of the objects of the invention is to provide a slip bowl with a downwardly tapered slip seat in which the bowl is provided with an inwardly extending flange restricting its bore at the upper end, and the slips are temporarily retained in the upper flared portion of the bore,

spread apart to permit the free passage of the inner casing, by being bolted to said flange.

Other objects of the invention will appear as the following description of a preferred and practical embodiment thereof proceeds.

In the drawings throughout the several figures of which the same characters of reference have been employed to designate identical parts:

Figure l is an axial section through a well control head embodying the principles of the subj ect invention;

Figure 2 is a cross-section taken along the line 2-2 of Figure 1;

Figure 3 is a cross-section taken along the line 33 of Figure 1;

Figure 4 is a longitudinal axial section through a modified form of the invention;

Figure 5 is a cross-section taken along the line 5-5 of Figure 4;

Figure 6 is a cross-section taken along the line 6--t of Figure 4;

Figure 7 is a longitudinal axial section through a further modified form of the invention;

Figure 8 is a cross-section taken along the line 8-8 of Figure 7.

Referring now in detail to the several figures, and first adverting to that form of the invention disclosed in Figure 1, the numeral l is a casing head having a lower threaded portion 2 adapted to be screwed to the top of an outer casing 3, having the usual flow line bores 4 above the threaded portion 2, and having a tapered seat 5 above the zone of the flow line bores 4 for the reception of the slip bowl unit, which in general is designated by the reference character 5.

Above the tapered seat 5, the bore of the casing head is cylindrical, and the upper portion of the slip bowl unit 6 has the same external shape.

Packing rings 1 seated in grooves 8 in the seating surface of the slip bowl unit eflfectively seal the joint between the slip bowl unit and the casing head.

The slip bowl unit includes a slip bowl 9 having a longitudinal bore therethrough, the upper part of which is restricted by the inwardly extending flange ID to an opening ll just large enough to freely pass the inner casing I2. At an intermediate portion the slip bowl 9 is similarly restricted by an inwardly projecting flange l3.

Between these flanges the bore of the slip bowl is expanded into a slip chamber having a downwardly tapered wall It. A plurality of slips l5 are arranged circumferentially within this chamher, the slips having outer tapered seating surfaces l6 cooperating with the tapered wall IA of the slip bowl unit, and with inner and preferably serrated faces I! adapted to grip the inner casing I2.

The slips are sufficiently shorter than the length of the slip chamber, so that they may lift from their seats on the tapered wall 14 when the casing I2 is elevated relative to theslip bowl unit. When in elevated position, the slips I5 contact with the upper flange H), the slips being imprisoned within the slip bowl by the flange ill when the inner casing I2 is in place.

The flange I0 is provided with a plurality of apertures [8, one for each slip, and the slips are provided with threaded sockets IS in their upper ends. Initially, the slips are bolted against the flange to by the bolts 20, which pass through the openings l8 and screw into the sockets IQ of the slips. When the slips are thus held upwardly from their seats in the slip bowl they are retracted radially so as to clear the path for the free passage of the inner casing.

It is obvious to those skilled in the art. that a compressible packing cannot be practically employed on top of the slips as a means to prevent leakage of gas under pressure from the well past the slips. The invention therefore contemplates the use of a metallic welded joint 2| between the top of the casing head and the inner casing. The weld of this joint also seals the openings l8 in the flange I0 after the bolts 20 have been removed.

In order to enable a fluid tight welded vjoint to termined point.

, by the seal formed by the packing. 26, which is an 7 closed by a threaded plug 31.

pressed into sealing contact with the slip bowl and inner casing l2 by the inner casing. A ring nut 24 screws into the lower end of the slip bowl against the packing. providing additional pressure. The seal between the lower end of the slip 5 bowl and the inner casing'also has a value as will appear, in permitting the sealed joint to be tested at any timeby the introduction of fluid under pressure into the slip bowl. The operation of the slip bowl unit is as foll0 lows: The slip bowl unit with the slips firmly bolted in an upward position against the inner .face of the flange lllis slipped over the end of the inner casing outside of the accessory blow-outpreventers which at the time are secured to the casing head. The ring nut 24 is adjusted to apply the proper sealing pressure to the packing 23. The inner casing, together with the slip bowl unit thus secured to the inner casing solely. by the irictional contact of the packing 23 with said casing,

is lowered through the blow-out-preventers until the slip bowl unit rests upon its seat in the casing head; The inner casing is then pushed downward through the blow-out preventer until it rests either upon the bottom of the well or down to, a prede 25 The accessory blow-out preventers are then removed. The bolts 20 are then unscrewed, letting the slips drop to their seating position upon the tapered wall 14 of the slip bowl;

The. slips in this position wedgingly gripthe inner casing. The inner casing may then be lifted through the slip bowl to any desired position and then released, when it will be at once gripped by the slips in its new position. When'the inner casingis properly set the joint between the topof the casing head and' the inner casing is sealed by the metallic weld 2| which, as has been stated, seals also the empty bolt openings I 8.

The particular'value of this form of slip bowl unit is that initially the slips are already in posi- I tion in the slip bowl unit and cannot become lost or displaced. They are also in position to admit v the passage of the inner casing without any manipulation of the slips.

installed, it is impossible that the slips may be disternal seat for sealingly supporting said slip bowl After having once been placed or removedwithout breaking the welded Y seal 21. and removing the inner casing from the.

'slip' bowl. 4

In Figure 4 a slipbowl unit or the captive slip type is shown, in which a threaded bore25 is proto the slip chamber to test intactness of the welded joint 2|. The fluid cannot escape by way of the lower part of the slip bowl, being blocked alternative form of packing to that shown in Figure l. This packing has a channel 21 in its top surface, communicating with the slip chamber,

and to which channel fluid pressure is admitted. The channel forms a flexible flap 28 engaging the surface of the inner casing I 2, the pressure of which against said casing is proportional to the 29 opening in the surface of the tapered seat 5 in the zone between the packing rings 30 of the slip bowl unit. The slip bowl is provided with inner and outer circumferential channels 3| and 32, respectively, in this same zone, said channels being in communication by way of a passage 33.- The inner channel 32 communicates with the longitudinal spaces between the slips. Apipe from the source of fluid under pressure may be connected to the threads 34 of the bore 29 and fluid pressure thus applied to the slip chamber. When the welded joint 2| is not under 'test, the bore 29 is closed by a suitable plug 35 screwed into the threads 36 of the bore 29.

While wehave in the above description disa scope of the invention as defined in the ap-- pended claims.

What we claim as our invention is:

1. In a casing control head for oil wells, a slip bowl unit comprising a slip bowl having an external seat for sealingly supporting said slip bowl within a casing head, said slip bowl having a bore therethrough for the passageof an inner pipe, the intermediate portion of said bore being.

expanded to form a slip chamber bounded at the top and bottom by inwardly extending slip retaining flanges, the side wall of saidslip chamber being downwardly convergent forming a slip seat, a plurality of slips within said slip chamber circumferentially displaced, means located above the zone of said external seat for releasably suspending said slips from said top flange in which.

suspended position said slips permit relative up and down movement between the inner pipe and to said slip bowl unit, said slips when released engaging said convergent wall for chocking the inner pipe against downward movement.

2. In a casing control head for oil wells, a slipbowl unit comprising a slip bowl having an ex-- taining flanges, the side wall of said slip chamber being downwardly convergent forming a slip seat, a plurality of slips within said slip chamber circumferentially displaced, means located above the zone of said external seat for releasably suspending said slips from said top flange comprising a plurality of spaced holes through said top flange and bolts in said holes engaging threaded sockets in the upper ends of said slips, in which suspended position said slips permit up and down movement of the inner pipe relative to said slip bowl unit, said slips when released engaging said convergent wall for checking the inner pipe against downward movement.

, v3. In a casing control head for oil wells, a slip bowl unit comprising a slip bowl having an external seat for sealingly supporting said slip bowl within a casing head, said slip bowl having a bore therethrough for the passage of an inner pipe, the intermediate portion of said bore being expanded to form a slip chamber bounded at the top and bottom by inwardly extending slip retaining flanges, the side wall of said slip chamber being downwardly convergent forming a slip seat, a plurality oi slips within said slip chamber circumferentiaily displaced, means located above the 'zone of said external seat for releasably suspending said slips from said top flange comprising a plurality of spaced holes through said top flange and bolts in said holes engaging threaded sockets in the upper ends of said slips, in which suspended position said slips permit up and down movement of the inner pipe relative to said slip bowl unit, said slips when released engaging said convergent wall for chocking the inner pipe against downward movement, said bottom flange being provided with an inwardly facing ring groove, and a compressible packing ring seated in said groove adapted to sealingly surround the inner pipe.

4. In a casing control head for oil wells, a slip bowl unit comprising a slip bowl having an external seat for sealingly supporting said slip bowl within a casing head, said slip bowl having a bore therethrough for the passage of an inner pipe, the intermediate portion of said bore being expanded to form a slip chamber bounded at the top and bottom by inwardly extendin slip retaining flanges, the side wall of said slip chamber being downwardly convergent forming a slip seat, a plurality of slips within said slip chamber cireumferentially displaced, and means accessible from above the top inwardly extending v flange for releasably suspending said slips from said top flange.

EDMUND J. ROACH'.

EDWARD F. COOKE Js. 

